[TenTec] emergency power via generator

[Dr. Gerald N. Johnson]

On Wed, 2007-03-07 at 13:27 -0500, John wrote:
> OK guys I thank all of you for the battery back up for emergency power information.   
> I have received the OK from the xyl to use some household funds to buy a generator 
> if it can also be used for some household appliances i.e..  Freezer, hotwater heater 
> some electric etc.  My question is this ... disregarding size what must I have in 
> a generator to be able to run my Ten Tec Orion II and computer ( re thought the 
> use of amplifier emergency use means I would be listening more and transmitting 
> less )  as well as some household items .  I may even be considering a propane 
> generator.  I am concerned in providing clean power to my radio and computer 
> what should I insist on in order not to damage my equipment ?  Thanks again   
> de   John Molenda  kb2huk

The water heater is the killer. Likely 4 KW. Fortunately unless its very
poorly insulated and the family insists on long showers, it can hold
half a day or a day without power. An insulating jacket is generally of
benefit unless its a recent high efficiency (e.g. well insulated) model.
The insulation pays anyway.

The orion and computer need probably less than 500 watts.

The furnace and its computer if new may demand clean power without too
much distortion of the waveform. That can knock out some low priced
generators.

As for power rating, its a trade off between starting motors (furnace
fan, A/C, freezer and refrigerator) and light load fuel consumption.
Starting most motors takes a surge current 5 to 6 times running current.
Starting them all at the same time gets tough.

I'm seeing 10 to 13 KW generators being installed on TV home shows, but
these are a bit on the upper end of scale. 

In any case a major hunk of the cost is a manual or automatic transfer
switch to isolate the emergency loads from the power line (for safety to
the linemen and for the generator, you can't supply the whole
neighborhood).
-- 
73, Jerry, K0CQ,
All content copyright Dr. Gerald N. Johnson, electrical engineer